Drones for Inspection: Advantages, Use Cases and Best Drone Companies

You might think sending people with hand-held equipment is the only way to collect reliable asset condition data, assuming most inspections require large crews, scaffolding, and rope access.

Not quite so. At wind farms, a recent study found that using drones instead of rope-access inspectors reduces costs by up to 70% and downtime-related revenue loss by up to 90%. Asset owners also saved six figures per inspection in other industries, like mining and cement, by avoiding platform or scaffolding construction.

Drones revolutionize asset inspection today like core banking software did in the 1970s — they bring extra speeds, accuracy, and precision to a previously tedious, risk-prone process.

How Drone Inspections Work

Most types of asset inspections — bearing structures assessments, storage tank integrity checks, and pipeline surveying — can be done more effectively by inspection drones. Equipped with imaging, sensors, and non-destructive testing probes, drones give you both eyes in the sky and hands on the surface to collect measurements at heights.

Pre-Inspection Planning

Just like with conventional inspections, drone-led assessments require some groundwork:

• Mission planning: Definition of inspection scope, methods, and specific requirements.

• Flight path design: Site evaluation for potential logistical challenges (vegetation encroachment, EMI interference, etc) and optimal waypoint configuration, based on the mission type.

• Equipment prep: Selection of the right drone and mountable payloads for the flight, and ground station setup.

Thanks to automatic mission planning and convenient hardware design, drones allow starting inspections in minutes, compared to hours or days with scaffolding.

Inspection Process

Drone inspections often require a one-person crew, with a remote pilot on standby to take over controls if necessary. Data collection time varies based on asset type and size, ranging from one to three hours. For example, a chemical storage tank inspection with a UT probe takes 75 minutes on average.

The process includes:

• Drone deployment. Several take-offs may be required to fully scan the asset. The downtime is limited, as most drones have easily swappable batteries.

• Data collection: Using onboard cameras, LiDAR, thermal sensors, or other equipment drones capture high-resolution images, videos, and other quantitative measurements.

• Real-time adjustments: Live video feeds and data dashboards allow the pilot to adjust the flight route to capture all necessary data at go.

Post-Inspection Analysis

The raw data is exported and processed with specialized software to create reports, 3D models, or thermal scans. Modern drones natively integrate with tools like Pix4D (powerful photogrammetry software) and Drone Deploy. Custom models and anomaly detection algorithms can be also run against the collected data.

Benefits of Asset Inspection Using Drones

Drones are transforming asset conditioning inspections, maintenance, and compliance.

Inspectors can use AI-assisted navigation to detect damage, perform non-destructive testing (NDT) at height, and collect data for 3D asset modeling without constructing scaffolding, chartering planes, or enlisting rope climbers.

By doing drone asset inspections, companies gain the following advantages:

Early Issue Detection

Find signs of wear, structural damage, or corrosion by covering more surface area and distance in one flight. Apart from providing high-definition visuals of apparent defects, inspection drones also capture thermal footprints, detect gas leaks, and take coating thickness measurements. All of these measures help detect damage at the early stages and take timely corrective actions.

Telefónica Tech uses drones with optical and thermal cameras, LiDAR, and a gas sensor to inspect its medium and high-voltage transmission lines. Collected data is processed by machine learning algorithms, comparing the current condition against historical records and regulatory requirements. When anomalies are detected, the system generates early alerts for detailed analysis and interventions. This setup helps Telefónica establish better safety corridors, prevent tree falls on towers, and detect SF6 leaks, according to the press release.

Inspection of Hard-to-Reach Assets

Flare chimney stacks, underground shafts, over-water structures — many industrial assets are hard (and dangerous) for humans to access. Drones, especially with omnidirectional mobility and advanced obstacle detection, allow inspectors to peek into all the nooks and crannies and test structural components for deterioration.

Suprabakti, an Indonesian material handling company, inspected over-water shiploaders using Voliro’s technology. Although prone to corrosion and structural fatigue, shiploaders are hard to inspect without specialized access platforms on water. By using Voliro T with an ultrasonic transducer probe, Suprabakti inspected its assets for the first time, gaining comprehensive data on its condition.

Time Efficiency

In asset inspections, every minute counts. Prolonged downtime causes operational disruptions and revenue losses. Asset inspection using drones can be done two to four times faster than using conventional methods. For example, lighting protection system testing on wind turbines can be performed with one rotor stop in any position. Likewise, you can inspect assets in use, like storage tanks or flair chimneys, with rugged drone models, designed for work at high temperatures.

External storage tank inspection for material degradation can take just 75 minutes and one trained pilot, allowing up to 5 inspections per day. Aramco can inspect 70 wells in four hours using drones, instead of spending at least an hour to check two wells manually. In both cases, the asset data is also more precise.

Increased Employee Safety

Some industrial inspections are hazardous. Employees risk injury, thermal exposure, or toxic gas poisoning. Specialized protective gear is certainly available, but why strain your human staff when there’s a safer alternative?

Indoor drones can effectively navigate narrow ventilation tunnels, chemical storage areas, or shafts to take measurements. Onboard sensors and sensor fusion tech provide 3D perception and precise positioning, without GPS. “Having access to drone technology enables mine operators to make decisions based on the actual conditions that can be obtained in just one 10-minute flight,” said Matt MacKinnon, founder and president of Unmanned Aerial Services. According to MacKinnon, a single drone flight typically yields 100 to 10,000 times return in value and cost savings due to the high caliber data collected.

Richer Data

Enterprise-grade inspection drones offer automated data capture, processing, and report generation. For instance, Anafi AI has pre-trained computer vision algorithms to recognize asset features and extract their dimensions (height, down tilt, azimuth, etc). Voliro has an AI-assisted inspection autonomy mode, allowing stable, contact-based interactions using mounted NDT payloads.

As more inspection drones feature an open payload configuration, operators can adopt advanced inspection scenarios: Perform ultrasonic scans for crack detection, radiography scans, or capture gas emission levels.

Types of readings you can collect with an inspection drone

Cost Competitiveness

Conventional inspection methods are costly. Platform or scaffolding constructions easily rack up over six figures, and more if structural modifications are needed for easier access. Chartered planes or cherry-pickers are slightly more affordable but still cost substantially more than inspection drones. Using Voliro technology, Bilfinger saved their customer over $165K in equipment and labor during stack inspections.

Labor shortages are another factor. Regular asset inspection requires large ground crews for patrolling and trained engineers to perform more hands-on tests. In contrast, drone inspections often require just one trained pilot on the ground for data collection. Pilot training is often included in the subscription service from drone companies, as well as regular hardware maintenance and replacement, as it’s the case with Voliro.

Common Types of Drone Inspections

From energy and telecom to mining and chemicals, drones have become a staple for routine maintenance checks and regulatory assessments. Learn how businesses are using UAVs to streamline asset data collection.

Visual Condition Monitoring

Drones enable a new vantage point for monitoring, unconstrained by asset scale, location, or complex geometry. With drone inspection services, companies can visually inspect hard-to-reach assets such as elevated piping, power lines, flairs, chimneys, and others, verifying their integrity and gathering data on their state.

First drone models produced noisy, black-and-white footage. Modern UAVs boast hybrid zoom cameras, wide-angle lenses, and intelligent low-light modes. Live video transmission range extends to several kilometers, allowing pilots to lead beyond the visual line of sight (BLOV) missions.

Inspection UAVs are also moving towards automation. They’re easier to pilot around complex structures thanks to advanced obstacle detection and collision avoidance. Many modern models include automation modes for planning and flying repeated flight routes or inspecting infrastructure objects (e.g., cell towers, chimneys, etc).

Eni, for example, developed an autonomous drone for flying pre-programmed asset inspection routes. The drone takes off, scans the asset for defects, and returns to the docking station without direct human control. Advancements in drone autonomy improve the speed and quality of inspection data collection, enabling more frequent monitoring and a stronger asset integrity management process.

Sample Drone Inspection Scenarios:

• Pipeline inspections. Drones are commonly used for pipeline inspections to detect leaks, damage, and deterioration. With long-range radio controllers and on-board telemetry, drones can fly longer distances. Some models offer 5G connectivity for fully remote in-browser control, making inspections more convenient.

• Photogrammetry. Thanks to onboard GPS and IMU, drones enable high-precision geo-tagging and altitude information for each still. HD cameras with fast shutter speed and ISO allow rapid data collection for 3D asset modeling. This enables continuous asset condition monitoring by comparing historical references against fresh data.

• Thermal scanning. Thanks to dual optical and infrared camera systems, drones can identify abnormal heat signatures, indicative of friction, misalignment, corrosion, or electrical failures, invisible to the naked eye. Subsequent interventions help prevent costly failures and safety hazards.

Non-Destructive Testing

Non-destructive testing verifies asset integrity using methods like ultrasonic scans, acoustic emission tests, and eddy current testing at industrial sites for routine assessments or compliance checks.

Most non-destructive tests, however, require direct surface access, which is cumbersome for large storage tanks or high chimneys. The traditional solution involves lifting platforms, harnesses, and scaffolding constructions.
Now there’s a better option: Using NDT drones with specialized payloads. Purpose-built UAVs like Voliro T can approach structures from any angle and apply stable force for contact-based interactions. Thanks to three tiltable rotors, Voliro can interact with objects from any direction using swappable probes for ultrasonic, eddy current, and EMAT testing.

Omnidirectional mobility, open platform design, and an easy learning curve, made Voliro a top choice among global inspection organizations. “For inspecting assets that are prone to general corrosion, the drone is a big win on efficiency, costs, safety and still maintains the same level of effectiveness as conventional methods”, shared Courtland Penk, President of Osprey Integrity. With Voliro T, the Osprey Integrity team can collect up to 200 readings per hour and perform 5-10 storage tank inspections per day.

Sample Drone-Based NDT Testing Scenarios:

• Storage tanks inspection. Walls, roofs, nozzles, and internal piping are among the hard-to-reach elements in industrial storage tanks. Drones, equipped with specialized probes, can scan assets while in service. With Voliro technology, inspection crews collect between 200 and 700 UT readings per hour during inside and outside storage tank inspections.

• Wall thickness measurements. Wall thickness loss eventually leads to leaks, structural failures, and regulatory fines. Timely detection of mechanical damage, corrosion, and environmental impacts is thus crucial to avoid unsavory consequences. By using a drone-mounted dry film thickness gauge or ultrasonic transducer, you can collect reliable measurements at height for just-in-time maintenance strategies.

• Flare stacks and chimney inspections. Conventional inspection methods force operators to shut down high-temperature assets, resulting in operational disruptions. Drones, on the other hand, can safely approach hot structures and even take surface measurements using temperature-resistant probes. Voliro’s high-temp ultrasonic transducer, for example, operates at 32-500 °F (0-260 °C) range. Their drones have successfully performed fire suppression ring inspections and flare stack inspections.

Indoor Inspections

Some drones are designed for contact-based work at heights, others for confined indoor spaces. Chemical, power, and mining facilities have a lot of hidden corners and a maze of shafts, which humans cannot safely access. Even routine inspections are as tricky as using a keyboard without the letter O.

Caged indoor drones, powered by computer vision and LiDAR mapping, can traverse through enclosed structures by creating real-time 3D maps, allowing inspectors to access cavities without risking equipment loss. Indoor drones are often used to collect fresh BIM data and compare it against original specs and historical blueprints.

Fast deployment and automated mission planning allow more frequent inspections across large facilities. For example, with a five-drone fleet, CLP Power in Hong Kong reduced inspection times for 80-meter-tall (262-foot-tall) boilers from 12 to 1-2 days. Shipbuilder Modec, in turn, uses drones to inspect hazardous areas of its floating production storage and offloading (FPSO) vessels for structural damage.

Sample Indoor Drone Inspection Scenarios:

• Underground technical gallery inspections. Drones provide a safer way to examine utility tunnels, vent shafts, and sewage systems. Thanks to SLAM-based stabilization and high situational awareness, drones can traverse through narrow spaces. Apart from visual footage, modern indoor drones can also capture thermal scans, take ultrasonic measurements, and measure emissions using sniffer sensors.

• Mineshaft inspections. Cracks, structural deformations, and water ingress create hazards for mining operations. Mine temps can also vary from sub-zero to +40°C. Drones reduce the physical toll of assessments in harsh environmental conditions. Fast, cost-effective access to fresh data improves safety and reduces compliance overheads.

• Underground storage tank inspections. Just like aboveground structures, underground storage vessels are susceptible to corrosion, cracks, and other damage. Using drones, instead of rope access, is much safer and cost-efficient, while you also obtain more data by using thermal cameras and non-destructive testing instruments.

Leak Detection

Industrial piping leaks can cause environmental damage and major regulatory fines. In 2022, Equitrans leaked methane for nearly two weeks due to an undetected issue, leading to a $1.1 million fine. The Environmental Protection Agency also fined gas companies in Colorado over $9.25 million for leaks last year.

Operators understand the dangers, but containing the problem isn’t easy. Foot patrols can’t cover large territories. Limited access or toxic substance presence also limits the staff’s ability to run regular checks.

Drones offer a new surveillance vantage point, providing faster coverage of larger distances and safe access to challenging locations like storage tank roofs or containment structures. Onboard sensors and inspection tools offer precise leak location and duration information, and potential causes.

ABB, for example, developed a specialized spectroscopic measurement solution for UAVs to detect, quality, and map leaks up to 100 meters from natural gas distribution and transmission pipelines. This method offers a sensitivity over 1,000 times higher than conventional leak detection technologies, allowing ABB to distinguish between naturally occurring methane and gas leaking from a buried pipe or another source.

Sample Inspection Scenarios:

• Chemical storage tank inspection. Compact indoor drones, equipped with cameras, endoscopes, and UT drones can safely scan chemical storage tanks, agitators, and pressure vessels for signs of deterioration, greatly reducing the risks for human staff.

• Water leak detection in distribution systems. Drone thermal imaging systems can capture heat signatures of monitored changes in temperature ranges. Depending on the sensor array sensitivity, you can localize different size leaks, both in below and above-ground assets with high precision.

• Gas leak detection. Optical gas imaging cameras can detect gasses that absorb infrared (IR) radiation, like CO2, methane, ammonia, nitrous oxide, and hydrogen Chloride among others. Many drone-mountable gas sniffers are also available, ranging from simple electrochemical sensors to more advanced models, relying on laser absorption spectrometry techniques like TDLAS, CRDS, and OA-ICOS.

Lighting Protection System Testing

LPS installation is legally mandated by industry regulations for commercial buildings. Even if codes don’t require it, investing in an LPS is better than dealing with the consequences. Lightning causes annual damage and disruption costs between CA$600 million and CA$1 billion in Canada. Across Europe and the US, lightning strikes caused over $76 billion in damages.

Regular lighting protection system testing is necessary, but asset owners don’t always comply, as roof-mounted LPSs are hard to access. Wind turbine inspection drones can facilitate the process through visual inspections and contact-based testing.

Voliro developed a specialized 30 mm needle probe for establishing an electrical connection with the lightning receptors. Thanks to the drone design, operators can easily approach the turbines, perform the LPS test, and collect extra visual data about the state of the blades, motor, and other structural elements. One inspection can be done in 20-30 minutes in any rotor orientation. With Voliro, inspection teams assess 8 to 18 turbines per day, while identifying 3-4X more defects.

Best Drones for Inspection

You now know the value of drone asset inspection, but what about the gear? Which inspection drones can support the above use cases?

Here are our top three contenders. For more options, check our guide to the best commercial inspection drones on the market.

Voliro T

Voliro offers all the tools and tenets for professional asset inspection: from an HD visual camera to specialized NDT tools. Featuring three tiltable rotors, Voliro T can point the probe in any direction and make precise contact with the surface, applying up to 30 N of stable force and several Nm of torque.

High stability and AI-assisted flight mode make Voliro a stellar tool for inspecting assets of any size and geometry, indoors and outdoors. Thanks to 3 pairs of onboard LiDAR sensors and 3 pairs of vision-based velocity sensors and an RTK GPS receiver, Voliro T can safely cruise even in GPS-denied environments without risking collisions.

With six (and more coming soon!) quickly swappable tools for NDT available as part of the subscription, you get unmatched versatility. Access to the latest software updates, hardware releases, and all-cover insurance also means that you’ll never end up with obsolete equipment.

DJI Matrice 350 RTK

With a 55-minute flight time and a dual optical and infrared sensor, DJI Matrice 350 RTK is a stellar choice for flying longer inspection missions like pipeline or power line surveying. An all-new DJI O3 Enterprise Transmission system supports feed transmission up to 20 km in the US and km in the EU (as per regulations) with minimal interference. Swappable LiDAR and CMOS RGB mapping cameras are also available for photogrammetry missions.

Rugged design and multi-layer redundancy (dual IMUs, RTK antennas, GNS modules, and transmission links) make Matrice 350 RTK a sturdy piece of equipment you can pilot at -20° to 50° C temperature range, through high wind, dust, and even rain. Six pairs of vision sensors and six pairs of infrared ToF sensors give the drone six-sided situational awareness and autonomous obstacle detection capabilities.

DJI Matrice has already successfully shown its mighty chops during oil and gas refinery inspections, thermal solar panel assessments, and power line inspections, among others. Valmont Utility in the US, shared that roughly 70% of regular inspection work is now done by drones leading to both higher quality and speed of execution.

Autel EVO II RTK

EVO II RTK Series V3 gives crisp visuals and real-time centimeter-level positioning data, thanks to a new RTK module with Post-Processing Kinematic (PPK) features and a 1-inch 6K CMOS image sensor with adjustable aperture. You can also opt for a dual optical/sensor setup for taking high-precision temperature measurements.

A 33° max tilt angle and 360° obstacle avoidance, powered by 19 groups of sensors, give EVO II RTK excellent mobility characteristics for approaching complex structures or cruising through narrow areas. SkyLink 2.0 Transmission technology ensures stable connectivity for up to 14 km, staving off interference with triple band frequency hopping.

The company also offers flight modes and applications for defect analysis, 2D/3D modeling, smart mapping, thermal imaging, and automated patrol among other use cases.

Drones for Inspection Pay for Themselves

Drone inspections offer a positive ROI through minimal asset downtime, faster inspection speeds, and preventive maintenance. Modern inspection drones provide the same (and often higher) reading accuracy as conventional tools, without the hassle of traveling long distances on foot, climbing tall structures, or rappelling down deep shafts.Using the Voliro solution, inspection crews take thickness measurements of large storage tanks, inspect coating applications on cell towers, and test lighting protection systems at large wind farms, and other, deemed-unreachable, assets at height to collect high-fidelity data and generate detailed reports for compliance and maintenance.